1. Field Of The Invention
The invention relates to new 1,3-cyclobutanedione-bisketals as well as processes for their production and for their use, especially for the production of squaric acid.
2. Background Art
Squaric acid (1,2-dihydroxycyclobutene-3,4-dione) is a useful intermediate product for the production of dyes, herbicides and pharmaceutically active ingredients. For a long time no economical production process for squaric acid was known, it has been possible in the meantime to produce squaric acid from 3-acetoxy-2-cyclobuten-1-one ("triketene") or from 1,3-cyclobutanedione or the enolates obtainable from it (European Published Patent Application Nos. 442431 and 444563). However, these processes generally require an expensive isolation of the triketene or of the 1,3-cyclobutanedione having little stability.